African American women have 1.5 times the rates of preterm birth (PTB) (<37 weeks completed gestation) compared with non-Hispanic white women. This disproportionately high PTB rate in African Americans is a persistent health inequity that leads to high child mortality, morbidity, and developmental delays. In the U.S. approximately $26 billion are spent annually on health care costs for infants and children that were born prematurely. Recent attempts to explain the high PTB rates in African American women have focused on social stressors, such as disadvantaged neighborhoods, racial discrimination, and stressful life events. These social stressors may lead to PTB by increasing women?s emotional stress levels. Not surprisingly, emotional stress along with levels of the stress hormone cortisol and systemic inflammation - both physiological responses to stress - have all been related to higher risk of PTB. In contrast, one?s psychosocial resources (e.g., social support) can lessen emotional stress and have protective effects on PTB. Little is yet known about the pathways by which social stressors affect inflammation, and ultimately PTB. The objective of the proposed study is to determine how social stressors alter inflammation during pregnancy and lead to PTB in African American women. We aim to: 1) determine the pathways by which social stressors affect PTB; and 2) describe social stressors, emotional stress and psychosocial resources; the associations among these concepts; and their impact on PTB from women?s perspectives. In this longitudinal convergent mixed methods design, we will enroll 1,500 African American women who live in the Detroit metropolitan area. We will collect data on social stressors, emotional stress, and psychosocial resources through questionnaires and administrative (e.g., census) data. This will be done three times prenatally. At these same time points, levels of cortisol and systemic inflammation will be determined from hair and blood samples, respectively. We will also obtain birth data from the prenatal and hospital records. In a subsample of 60 women, semi-structured interviews will be conducted to more specifically understand the associations among social stressors, emotional stress and psychosocial resources; and their impact on PTB. We will conduct a variety of statistical, qualitative and mixed methods analyses using both quantitative and qualitative data to determine answers to the aims of our study. We will also consider the timing of pregnancy in our analyses, as the prenatal data are collected at three distinct time points. The proposed research is highly relevant to NIH?s mission to elucidate mechanisms underlying health disparities in PTB. Insights gained from this mixed methods approach may lead to the development of an individualized PTB risk profile based on a woman's social stressors and biomarkers which will have potential use in clinical practice and be a target for culturally appropriate interventions to reduce PTB incidence in African American women, and will generate new perspectives for future research in other racial groups through our detailed focus on this high risk group.